In the art of window and door components and trim, such components have historically been made of 100% natural wood. Residential windows are commonly manufactured from milled wood products that are assembled with glass to form double hung or casement units. Wood windows, while structurally sound, useful and well adapted for use in many residential installations, can deteriorate under certain circumstances. Wood windows require painting and other periodic maintenance. Wood windows are costly due to the increasing scarcity of suitable wood for construction, particularly clear wood products. As an alternative to wood, metal components are often combined with glass and fabricated into windows. Metal windows however, typically suffer from substantial energy loss during winter months.
In recent years, extruded thermoplastic materials have been used in window and door manufacture. Filled and unfilled thermoplastics have been extruded into components to form plastic windows and into seals, trim, weatherstripping, coatings, and other window construction components. Thermoplastic materials such as polyvinyl chloride (PVC) have been combined with wood members in manufacturing some windows for certain performance and cost advantages. The plastic is often colored with a coloring agent to give a wood-like appearance or to match the colors of the surrounding area. Although the colored plastic may appear somewhat wood-like, it cannot be painted or sanded or stained like real wood. For this reason, it was difficult, if not impossible, to match plastic components to natural wood surroundings. One prior art solution wrapped the plastic with a foil or laminate having a wood-like appearance. Still another solution used an epoxy to glue wood laminates onto the thermoplastic. Such laminates however are expensive and easily damaged.
It is known in the art to combine different forms of plastic with different forms of natural fiber such as wood flour, crushed shells of nuts, and other natural materials. The purpose of such previous combinations has been to enhance the physical properties and lower the cost of the product. However, such materials have not been successfully used in the form of a structural member that is a direct replacement for wood. Typical common extruded thermoplastic materials have been found not to provide thermal and structural properties similar to wood or other structural materials. Accordingly, a substantial need exists for a composite material that can be made of polymer and wood fiber with an optional, intentional recycle of a waste stream. A further need exists for a composite material that can be extruded into a shape that is a direct substitute for the equivalent milled shape in a wooden or metal structural member. This need requires a coefficient of thermal expansion that approximates wood, a material that can be extruded into reproducible stable dimensions, a high compressive strength, a low thermal transmission rate, an improved resistance to insect attack and rot while in use, and a hardness and rigidity that permits sawing, milling and fastening retention comparable to wood.
Further, companies manufacturing window and door products have become significantly sensitive to waste streams produced in the manufacture of such products. Substantial quantities of wood waste, including wood trim pieces, sawdust, wood milling by-products, recycled thermoplastic including recycled polyvinyl chloride, have caused significant expense to window manufacturers. Commonly, these materials are either burned for their heat value in electrical generation, or are shipped to qualified landfills for disposal. Such waste streams are contaminated with substantial proportions of hot melt and solvent-based adhesives, waste thermoplastic such as polyvinyl chloride, paint, preservatives, and other organic materials. A substantial need exists to find a productive, environmentally compatible process for using such waste streams for useful structural members and thus, to avoid returning the materials into the environment in an environmentally harmful way.
Therefore, the prior art teaches that conventional window and door manufacture has commonly used wood, metal and thermoplastic composites or a combination thereof. Wood windows, while structurally sound, can deteriorate under certain circumstances and require painting and other periodic maintenance. Thermoplastic, metal or thermoplastic composite windows have overcome this problem, but have created others. Metal windows typically suffer from substantial energy loss during winter months. Thermoplastic or thermoplastic composite windows, although structurally sound, have no wood on the inside which is generally preferred by the consumer. To overcome this shortcoming, manufacturers have used various alternatives. One such alternative is a combination of wood, metal or thermoplastic for the manufacture of windows which places the metal or thermoplastic on the outside of the window (thereby eliminating painting), while having the inside of the window as a wood surface, which can then be sanded, painted or stained. The thermoplastic or thermoplastic composite manufacturer often wraps the surfaces visible on the inside of the window with a foil or laminate having a wood-like appearance. Such foils however, are expensive, difficult and time consuming to apply and are easily damaged by the end-user. At best, they are only an imitation which is obvious to the end-user and cannot be sanded or stained. Another approach is to glue wood veneer on the inside of the window surfaces. This however, is difficult to apply and extremely costly.
The present invention relates to a new and improved stainable and paintable article and method of making the article which is effective in use and overcomes the foregoing difficulties and disadvantages while providing better and more advantageous overall results.